1. Field of Invention
This invention generally relates to telecommunication service and, more particularly, to a device that automatically forwards telephone service upon detecting a triggering event.
2. Description of Related Art
In recent years, the vast majority of the industrialized world has become accessible via the public switched telephone network (PSTN). Most commonly, this accessibility has been implemented through conventional telephone systems. A conventional telephone system may be considered to be and is hereinafter included in the general category of wire-line systems, i.e., telecommunications systems that transmit communications over lines such as copper, cable, or fiber optic lines. Thus, a unit that operates in a wire-line system may be referred to as a wire-line unit. For example, corded and cordless telephones are common examples of wire-line units.
The popularity and widespread acceptance of wireless communication systems have brought about the development of systems that work as an adjunct to wireless communication systems and with the PSTN. An example of an adjunct to wireless communication systems is the fixed wireless (FWL) system. An FWL system allows a user to effectively convert certain conventional wire-line telephones into extensions of the user's wireless telephone or unit. In particular, an FWL system usually includes a cell phone physically connected to one or more conventional telephones within a discrete location, such as a home or office. The FWL system allows the user to make use of the wireless communication system through the connected conventional telephones. These extensions to the cell phone may provide the user with certain advantages. Yet, these FWL systems do not provide the user with access to the PSTN independently of the wireless communication system. Such lack of direct access to the PSTN could be critical in the event that one of the wireless communication links, from and including the cell phone to the wireless communication system, is not functioning properly.
Another example of an adjunct to wireless communication systems is a type of system referred to herein as “base station” technology, but also commonly known as “cellular cordless” technology. Base station technology allows a user to make use of certain aspects of conventional telephone systems and of wireless communication systems. To utilize this base station technology, a user who has access to the PSTN and who also has access to a wireless communication system must purchase both a specially equipped base station and a specially equipped cell phone, e.g., such equipment is manufactured by Motorola Inc., 600 North U.S. Hwy 45, Libertyville, 111. 60048 and is available as a Personal Phone Series (PPS) system. The base station is located typically at the user's base of operation, be it a residence, office or the like. The base station is connected to the PSTN and includes a mechanism for detecting the proximal presence of the user's cell phone when that cell phone is within a certain limited geographical distance of the base station. In essence, the base station functions as a cell site which provides a continuous “control channel” in a manner similar to a conventional cell site. The base station is different from the conventional cell site in that it utilizes a non-standard control channel that changes based on internal interference avoidance algorithms.
Normal operation of the specially equipped cell phone includes a periodic scan of the designated control channel to determine whether the cell phone is within range of the base station. If so, the cell phone and base station “handshake” in a manner well known in the telecommunications field. The result of the handshake is registration of the cell phone with the base station, which registration triggers an operational switch to the cell phone operating with the base station from the cell phone operating with the cellular network. The wireless communication system is then notified of the registration. Typically, the base station then functions as a wire-line unit and is assigned a wire-line number. Accordingly, after the wireless communication system is notified of the registration of the cell phone with the base station, the wireless communication system does not accept or continue handling the communication directed to the number associated with the cell phone in the conventional manner. Instead, the wireless communication system effectively relinquishes the communication to the PSTN. Thereafter, the communication is routed in a conventional manner through the PSTN to the base station as if it were a wire-line call.
In response to receiving the communication through the PSTN, the base station transmits the communication to the cell phone in the same manner as communications would be transmitted to a cordless telephone in a wire-line system. Effectively, the cell phone functions as a cordless telephone. By this relay of the communication, the wireless communication system is not involved in the communication. Thus, expenses associated with cellular services and usage fees are obviated with respect to this communication. In other words, even though this communication was initially directed to a number associated with a cell phone, the communication is ultimately connected as a conventional telephone call or wire-line call. Thus, the user is not charged cellular service charges for the communication.
In summary, base station technology allows increased flexibility for a user because the user may use a cell phone in a manner that does not incur the significantly higher usage fees typically accompanying cell phone use. The benefits of base station technology, though, are predicated upon several factors. First, the user must purchase a specially equipped cell phone and also purchase an accompanying specially equipped base station. Second, the cell phone must be within proximal range of its base station. Even after these criteria are met, a user must still provide two telephone exchange numbers—one for the cellular service and one for the landline service. Finally, an individual who desires to implement base station technology will, after purchasing the specialized base station and cell phone, likely be left with a conventional cordless phone which is unusable in conjunction with the base station technology.
Applicant is aware of a cellular telephone call-forwarding system using an adjunct device. That system provides a mechanism for routing calls intended for a wireless unit to an alternate destination number, specifically a wire-line number. In that system, the wireless unit is placed in a cradle-like portion of an adjunct device to automatically initiate a call forward request in response to a triggering event. Subsequently, all calls directed to the wireless unit will be routed to a predetermined destination number.
However, the present invention is an improvement on such prior art systems. Specifically, the prior art systems require advanced processors located in the adjunct device to perform the call forward functions. For example, U.S. Pat. No. 6,151,500 (hereinafter the '500 patent), assigned to one of the parent corporations of the assignee of the present invention, uses a converter device to detect a threshold amount of current drawn from the battery source of the wireless unit when placed in the cradle as a triggering event to initiate a call forward request. In response to the triggering event, the call forward device itself transmits a message to the wireless communications network thereby providing instructions to direct subsequent calls originally destined to a wireless number to a different predetermined location. Since the call forward adjunct device transmits the call forward message, the processing device in the '500 patent teaches methods to construct the message and to detect the current flow that initiates the triggering event. Additionally, the '500 patent requires that the call forward device have a communications channel to the wireless communications network.
U.S. Published Patent Application No. 2003/0181202 A1 (hereinafter the '202 app.) (Also assigned to the Assignee of the 500 patent) teaches additional methods for pausing triggering events and providing call forward instructions to the wireless communications system. According to one embodiment of the '202 app., similar to the '500 patent, the call forwarding adjunct device constructs an SMS message and transmits the message to the wireless communications system. In that embodiment, the call forward adjunct device contains a memory that stores the operating algorithm and a destination number.
U.S. Pat. No. 5,933,774, (the '774 patent) similar to the '500 patent, teaches of a call forward adjunct device that initiates a modem connection to the wireless communications system to communicate the call forward request. This method requires both a connection to the wireless communications system as well as a dedicated PSTN line.
Each of these items is hereby incorporated by reference in their entirety.